CN117615893A - Molding apparatus and molding method, pouch-type battery case manufactured by the method, and secondary battery including the pouch-type battery case - Google Patents

Abstract

A molding apparatus according to embodiments of the present invention may mold a cup in a soft capsule. The molding apparatus includes: a mold, the soft envelope being disposed on a top surface of the mold and defining a first space in the mold recessed from the top surface; a stripper which is provided above the mold and fixes the soft envelope, and in which a second space is defined at a position corresponding to the first space; and a pressing portion configured to apply air pressure or hydraulic pressure to the soft capsule such that a portion of the soft capsule is stretched into the first space.

Description

Molding equipment and molding method, pouch-type battery case manufactured by the method, and And secondary battery including the soft pack type battery case

Cross-references to related applications

This application claims the benefit of priority from Korean Patent Application No. 10-2021-0111974, filed on August 24, 2021, which is incorporated herein by reference in its entirety.

Technical field

The present invention relates to a molding apparatus and method for molding a cup in a soft film, and more specifically, to a soft-pack type battery case manufactured by the method and two devices including the soft-pack type battery case. Secondary battery.

Background technique

Generally, secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. Such secondary batteries are being used in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, electric bicycles, etc., and in applications requiring high power such as electric vehicles and hybrid vehicles. Large products, power storage devices to store surplus power or renewable energy, and backup power storage devices.

Generally, in order to manufacture a secondary battery, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to manufacture a positive electrode and a negative electrode. Then, electrodes are stacked on both sides of the separator to form an electrode assembly. Furthermore, the electrode assembly is accommodated in the battery case, and then, after injecting the electrolyte thereinto, the battery case is sealed.

Such secondary batteries are classified into soft-case type secondary batteries and hard-case type secondary batteries according to the material of the case housing the electrode assembly. In a pouch-type secondary battery, the electrode assembly is housed in a pouch made of a flexible polymer material. Furthermore, in the hard case type secondary battery, the electrode assembly is accommodated in a case made of metal or plastic material.

Generally, a pouch-type battery case is manufactured by performing a pressing process on a flexible pouch film to form a cup portion. In addition, when the cup portion is formed, the electrode assembly is accommodated in the cup portion, and then, the side of the cup portion is sealed to manufacture a secondary battery.

In the pressing process, stretch molding is performed by inserting the soft film into a molding device such as a pressing device, and applying pressure to the soft film using a punch to stretch the soft film. This is described in more detail below

FIG. 1 is a schematic diagram of a molding apparatus according to the related art.

The molding apparatus according to the related art includes a mold 2 for placing the soft coating F and defining a molding space 2a, a demoulding device 3 disposed above the mold 2 and fixing the soft coating F and having an opening 3a. 3a Stretch the punch 4 of the soft film F. In addition, when the mold 2 and the ejector 3 rise relative to the punch 4, or when the punch 4 descends relative to the mold 2 and the ejector 3, the punch 4 can exert pressure on the soft coating F, so that the soft coating F A portion of is stretched into the molding space 2a, so that a cup 110 can be defined in the soft envelope F.

However, in the molding equipment according to the related art, in order to prevent the soft coating F from being pushed or damaged by friction during the movement of the punch 4 and the mold 2 relative to each other, it is necessary to mold the inner periphery of the punch 4 with the There is a predetermined gap g between the outer peripheries of the space 2a. Therefore, the peripheral surface 112 of the cup portion 110 defined in the soft envelope F may be inclined relative to the bottom surface 111 of the cup portion 110 . Therefore, an empty space occupied by an electrode assembly (not shown) is generated in the cup portion 110, so that there is a problem that the energy density of the secondary battery is reduced.

In addition, in the molding equipment according to the related art, when the punch 4 presses the soft coating F, stress is concentrated on the corners of the punch 4 . Therefore, when the cup portion 110 is formed deeply in the soft coating film F, the corners of the cup portion 110 are overstretched, so that there is a residual thickness thinning, and cracks or small holes appear at the corners of the cup portion 110 (pin-hole) problem.

In addition, there is a problem that the peripheral surface 112 of the cup portion 110 defined by the molding apparatus according to the related art is not sufficiently stretched, so that compressive force acts to cause wrinkles due to bending.

Contents of the invention

technical problem

In order to solve the above problems, one object of the present invention is to provide a molding apparatus and a molding method that, while molding the cup portion to have a sufficient depth, maintain a thick residual thickness at the corners of the cup portion.

In order to solve the above problems, another object of the present invention is to provide a soft-pack type battery case manufactured by the above-mentioned molding equipment and molding method, and a secondary battery including the soft-pack type battery case.

Technical solutions

A molding apparatus according to an embodiment of the present invention can mold a cup in a soft envelope. The molding apparatus may include: a mold, the soft coating film is disposed on a top surface of the mold and defines a first space recessed from the top surface; a soft capsule, and a second space is defined in the demolder at a position corresponding to the first space; and a pressing part configured to apply air pressure or hydraulic pressure to the soft capsule such that a portion of the soft capsule is Stretch into the first space.

The stripper may be provided with a cover configured to seal the second space on the upper side, a channel that communicates the pressing portion and the second space with each other is provided in the stripper or the cover, and the pressing portion is introduced or discharged through the channel gas to control the internal pressure of the second space.

The molding apparatus may further include: a flexible bag disposed in the second space to contact the soft envelope; and a bag body configured to seal the second space, the flexible bag being connected to the bag body, and the bag body The main body is provided with a channel that communicates the pressing part and the flexible bag with each other. The pressing portion can control the internal pressure of the flexible bag by introducing or expelling fluid through the channels.

The molding apparatus may further include a first punch inserted into the first space and having a curved surface protruding toward the soft capsule.

The middle part of the curved surface may be highest and the height of the curved surface may gradually decrease toward the inner circumference of the first space.

In a state where the first punch is inserted into the first space, the middle part of the curved surface may be disposed at a lower height than the top surface of the mold.

The first space may have a first width in a first direction and a second width in a second direction perpendicular to the first direction, and the curved surface may be part of an ellipsoid:

(where x is the coordinate in the first direction, y is the coordinate in the second direction, z is the coordinate in the vertical direction, a is half the first width, b is half the second width, and c is a value obtained by multiplying the average value of value a and value b by a correction constant k of 0.2 to 0.6).

The molding device may also be inserted into the first space and have a second punch facing the plane of the soft envelope.

Compared with the state of the first punch being inserted into the first space, the pressing part can apply greater pressure when the second punch is inserted into the first space.

The height difference between the flat surface and the top surface of the mold when the second punch is inserted into the first space may be greater than the height difference between the curved surface and the top surface of the mold when the first punch is inserted into the first space.

The molding apparatus may further include: a lower body disposed below the mold and in which a third space connected to the first space is defined; and a flexible bag disposed in the third space and expanded to in the first space to be in contact with the soft envelope; a bag body configured to seal the third space, and the flexible bag is connected to the bag body; and a sub-pressing part configured to be disposed on the bag body via Channels in the bag introduce or expel fluid to control the internal pressure of the flexible bag.

Molding methods according to embodiments of the present invention can mold a cup in a soft envelope. The molding method may include: a preparation process of inserting the soft coating between the mold and the demoulder; a fixing process of fixing the soft coating by the demoulder; and the pressing part presses the soft coating through the second space formed in the demoulder. A pressing process in which air pressure or hydraulic pressure is applied to the coating so that a portion of the soft coating is stretched to a first space formed in the mold.

The pressing process may include: a primary molding process, in which a first punch with a curved top surface is inserted into the first space of the mold, and a part of the soft coating is in close contact with the curved surface, wherein the curved surface protrudes upward. and a secondary molding process, in which a second punch with a flat top surface is inserted into the first space, and a part of the soft coating is in close contact with the flat surface.

The pressure applied to the soft envelope in the secondary molding process may be greater than the pressure applied to the soft envelope in the primary molding process.

Molding methods according to embodiments of the present invention can mold a cup in a soft envelope. The molding method may include: a preparation process of inserting the soft coating between the mold and the demoulding device; a fixing step of fixing the soft coating by the demoulding device; and applying air pressure or hydraulic pressure to the soft coating so that a part of the soft coating is A pressing process of stretching into the first space formed in the mold to mold the cup portion. The pressing process may include: a pre-molding process in which the first flexible bag disposed in the second space formed in the demolder stretches the soft wrap film into the first space; and the second flexible bag is expanded into the first space. , in an initial molding process of pressing a part of the soft envelope so that a part of the soft envelope is formed to protrude upward; and adjusting the internal pressures of the first flexible bag and the second flexible bag to be the same, so that the soft envelope A secondary molding process in which a portion is formed flat.

During the primary molding process, the internal pressure of the second flexible bag may be greater than the internal pressure of the first flexible bag.

The internal pressure of each of the first flexible bag and the second flexible bag in the secondary molding process may be greater than the internal pressure of the second flexible bag in the primary molding process.

A pouch-type battery case according to an embodiment of the present invention may include: a cup portion having a concave shape; and a platform provided on at least a portion of the periphery of the cup portion. The cup portion may include: a bottom surface; a plurality of circumferential surfaces configured to connect the bottom surface and the platform; and a corner portion formed from a pair of circumferential surfaces adjacent to each other among the plurality of circumferential surfaces and the bottom surface. formed by intersecting each other. The thickness of the corners may be 0.75 to 0.85 times the thickness of the bottom surface.

The angle formed by the peripheral surface relative to the bottom surface or platform may be 90 degrees to 95 degrees.

The corners may have a radius of curvature of 0.75mm to 1.25mm.

The cup may further include: a first edge at which the upper surface and the platform intersect each other and the first edge is rounded; and a second edge at which the bottom surface and the peripheral surface intersect each other, and a second edge at which the bottom surface and the peripheral surface intersect each other. The edges are rounded. The gap between the first edge and the second edge is 0.1mm or less

Each of the first edge and the second edge may have a radius of curvature of 0.1 mm or more and less than 0.5 mm.

The cup may further include: a first edge at which the bottom surface and the peripheral surface intersect each other and the first edge is rounded; and a second edge at which the upper surface and the platform intersect each other, and a second edge at which the upper surface and the platform intersect each other. The edges are rounded. A gap between the first edge and the second edge may be smaller than a radius of curvature of each of the first edge and the second edge.

A secondary battery according to an embodiment of the present invention may include: an electrode assembly; and a pouch-type battery case including a cup portion having a concave shape and a receptacle provided on at least a portion of the periphery of the cup portion. platform. The cup portion may include: a bottom surface; a plurality of circumferential surfaces configured to connect the bottom surface and the platform; and a corner portion formed from a pair of circumferential surfaces adjacent to each other among the plurality of circumferential surfaces and the bottom surface. formed by intersecting each other. The thickness of the corners may be 0.75 to 0.85 times the thickness of the middle part of the bottom surface.

beneficial effects

According to a preferred embodiment of the present invention, since the soft envelope is stretched by air pressure or hydraulic pressure to mold the cup, stress concentration on the corners of the cup can be minimized. Therefore, even if the cup portion is molded deeply, the remaining thickness of the corner portion can be kept thick, and cracks or small holes can be prevented from occurring in the corner portion.

In addition, during the process of molding the cup part, the peripheral surface of the cup part can be fully stretched. Therefore, it is possible to prevent the occurrence of wrinkles due to bending on the peripheral surface of the cup.

In addition, the radius of curvature of each of the edges and corners of the cup portion can be minimized, and the peripheral surface of the cup portion can be formed to be nearly vertical. Therefore, the appearance of the secondary battery can be sharp, and the energy density can be improved.

The effects of the present invention are not limited to the foregoing description, and therefore more diverse effects are included in this specification.

Description of drawings

FIG. 1 is a schematic diagram of a molding apparatus according to the related art.

Figure 2 is a schematic diagram of a molding apparatus according to an embodiment of the present invention.

Figure 3 is a bottom view of a mold according to an embodiment of the present invention.

4 is a flowchart illustrating a molding method performed using a molding apparatus according to an embodiment of the present invention.

5A to 5C are diagrams illustrating the operation of the molding apparatus according to the embodiment of the present invention.

6 is an exploded perspective view of the secondary battery according to the embodiment of the present invention.

FIG. 7 is an enlarged view of part A of FIG. 6 .

8 is a cross-sectional view showing the inside of the secondary battery according to the embodiment of the present invention.

FIG. 9 is an enlarged view of part B of FIG. 8 .

Figure 10 is a schematic diagram of a molding apparatus according to another embodiment of the present invention.

Figure 11 is a schematic diagram of a molding apparatus according to yet another embodiment of the present invention.

FIG. 12 is a flowchart illustrating a molding method performed using a molding apparatus according to yet another embodiment of the present invention.

13A to 13C are diagrams illustrating the operation of a molding apparatus according to yet another embodiment of the present invention.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. However, the invention may be implemented in several different forms and is not limited or constrained by the following examples.

In order to describe the present invention, detailed description of parts irrelevant to the description or related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and in this specification, reference numerals are added to components in the respective drawings. In this case, the same or similar reference numerals refer to the same or similar elements throughout the specification.

Furthermore, the terms or words used in the specification and claims should not be construed restrictively to ordinary meanings or dictionary-based meanings, but should be construed as consistent with the present invention based on the principle that the inventor can appropriately define the concept of the terms. range of meanings and concepts to best describe and explain his or her invention.

2 is a schematic diagram of a molding apparatus according to an embodiment of the present invention, and FIG. 3 is a bottom view of a mold according to an embodiment of the present invention.

The molding apparatus according to the embodiment of the present invention includes: a mold 10 with a soft coating F disposed on its top surface; a demoulding device 20 disposed above the mold 10 and fixing the soft coating F; and a mold stripper 20 for fixing the soft coating F. The pressing part 30 applies air pressure or hydraulic pressure. The molding apparatus may further include first and second punches 40 and 50 inserted into the first space S1.

The soft envelope F may have a predetermined thickness t. The soft wrap film F may be a laminated sheet laminated with a pair of resin layers provided on both outermost surfaces and a metal layer provided between the pair of resin layers.

The soft envelope F may be placed on the top surface of the mold 10 . A first space S1 that is concave downward from the top surface may be defined in the mold 10 . The first space S1 can be open to the upper side and the lower side. When the soft coating film F is placed on the top surface of the mold 10, the soft coating film F may cover the first space S1 from the upper side. In addition, the first punch 40 and the second punch 50 which will be described later may be inserted into the first space S1 from the lower side of the mold 10 .

The cross section of the first space S1 of the mold 10 may have a substantially rectangular shape. More specifically, the first space S1 may have a first width W1 in a first direction and a second width W2 in a second direction perpendicular to the first direction. That is, the first direction may be parallel to the horizontal direction of the first space S1, and the second direction may be parallel to the vertical direction of the first space S1. In addition, the first width W1 may be the horizontal width of the first space S1, and the second width W2 may be the vertical width of the first space S1.

The stripper 20 may face the mold 10 , and the soft coating F is interposed between the stripper 20 and the mold 10 . The stripper 20 may be configured to be elevated relative to the mold 10 . When the demoulding device 20 is raised, the soft coating F can be inserted between the mold 1 and the demoulding device (20). Then, when the demoulding device 20 descends, the soft coating F can be fixed between the mold 10 and the demoulding device. between 20 devices.

A second space S2 may be defined in the stripper 20 . The second space S2 may be defined at a position corresponding to the first space S1 of the mold 10 .

In this embodiment, the second space S2 may be close to the upper side and open to the lower side. More specifically, the demolder 20 may be provided with a cover portion 21 that seals the second space S2 from the upper side. The cover part 21 may be coupled to the demolder 20 as a separate configuration from the demolder 20 , or may be provided to be integrally formed with the demolder 20 .

A passage 21a may be defined in the cover part 21 to communicate the pressing part 30 to be described later with the second space S2. However, the present invention is not limited thereto, and the channel 21a may be provided in the demolder 20.

When the stripper 20 fixes the soft coating F, the soft coating F can cover the second space S1 from the lower side. That is, in a state where the soft coating F is fixed between the mold 10 and the demoulding device 20, a part of the soft coating F may be disposed between the first space S1 and the second space S2. Hereinafter, a part of the soft capsule F disposed between the first space S1 and the second space S2 is referred to as the target area 110 .

The pressing part 30 may apply air pressure or hydraulic pressure to the soft capsule F through the second space S2, more specifically, apply air pressure or hydraulic pressure to the target area 110. Therefore, the target area 110 can be stretched into the first space S1, and the target area 110 can be molded into a cup. Therefore, the cup is designated by the same reference numeral 110 as the target area 110 .

Since the target area 110 of the soft envelope F is stretched into the first space S1 and molded into the cup 110, the horizontal length of the cup 110 may be the same as or close to the first width W1 of the first space S1, and The vertical length of the cup portion 110 may be the same as or close to the second width W2 of the first space S1.

The arrangement of the pressing part 30 is not limited. In this embodiment, the pressing part 30 may apply air pressure to the target area 110 . For example, the pressing part 30 may include an air pressure pump.

More specifically, the pressing part 30 can control the internal pressure of the second space S2 by introducing gas into the second space S2 through the channel 21a and extracting it from the second space S2. Therefore, when the internal pressure of the second space S2 is higher than the internal pressure of the first space S1 (eg, atmospheric pressure), the target area 110 may be stretched by the pressure difference between the first space S1 and the second space S2. In the first space S1.

That is, since isostatic pressure is applied to the target region 110, in the process of stretching the target region 110, the thickness t of the target region 110 can be uniformly reduced as a whole. Therefore, stress concentration in the local area of the target area 110 can be minimized.

The first punch 40 and the second punch 50 may be inserted into the first space S1 from the lower side of the mold 10 . More specifically, the first punch 40 and the second punch may be alternately inserted into the first space S1.

For example, the first punch 40 and the second punch 50 may move horizontally relative to the mold 10 , and the mold 10 may move vertically relative to the first punch 40 and the second punch 50 . In this case, when the mold 10 is lowered with the first punch 40 aligned and disposed on the lower side of the first space S1, the first punch 40 may be inserted into the first space S1. In addition, when the mold 10 is lowered with the second punch 50 aligned and disposed on the lower side of the first space S1, the second punch 50 may be inserted into the first space S1.

However, the present invention is not limited thereto, and the mold 10 may move horizontally relative to the first and second punches 40 and 50 , or the first and second punches 40 and 50 may be elevated relative to the mold 10 .

The outer periphery of each of the punches 40 and 50 may be in contact with or adjacent to the inner periphery of the first space S1 of the mold 10 . This is because the soft film F is not inserted between the outer periphery of each of the punches 40 and 50 and the inner periphery of the first space S1.

The first punch 40 may have a curved surface 41 formed convexly toward the soft envelope F (more specifically, the target area 110 ). That is, the curved surface 41 may define the top surface of the first punch 40 . The middle part of the curved surface 41 may be the highest, and the height of the curved surface 41 may gradually decrease toward the inner circumference of the first space S1. More specifically, the curved surface 41 may have a shape corresponding to a portion of an ellipsoid.

In a state where the first punch 40 is inserted into the first space S1 , the target area 110 may be pressed by the pressing part 30 to be in close contact with the curved surface 41 of the first punch 40 .

After the first punch 40 is separated from the first space S1, the second punch 50 may be inserted into the first space S1.

The second punch 50 may have a flat surface 51 facing the soft envelope F (more specifically, the target area). That is, plane 51 may define the top surface of second punch 40 .

In a state where the second punch 50 is inserted into the first space S1 of the mold 10 , the target area 110 may be pressed by the pressing part 30 to be in close contact with the flat surface 51 of the second punch 50 .

4 is a flowchart showing a molding method performed using the molding apparatus according to the embodiment of the present invention, and FIGS. 5A to 5C are diagrams illustrating the operation of the molding apparatus according to the embodiment of the present invention.

The molding method according to this embodiment may include: a preparation process (S10) of inserting the soft coating film F between the mold 10 and the demoulding device 20; a fixing step (S20) of fixing the soft coating film F by the demoulding device 20; A pressing process (S30) in which pneumatic pressure or hydraulic pressure is applied to the soft coating F.

In the preparation process ( S10 ), the demolder 20 may be raised to a predetermined height relative to the mold 10 , and the soft film F may be inserted between the mold 10 and the demolder 20 . Therefore, the soft coating F can be placed on the top surface of the mold 10 .

During the fixing process ( S20 ), the demoulder 20 may be lowered toward the mold 10 , and the soft coating F may be fixed between the mold 10 and the demoulder 20 . Here, the target area 110 of the soft coating F may be provided between the first space S1 of the mold 10 and the second space S2 of the demolder 20 .

During the pressing process (S30), the pressing part 30 may apply air pressure or hydraulic pressure to the soft coating film F through the second space S2 of the demoulding device 30.

In this embodiment, the pressing part 30 may apply air pressure to the target area 110 . The pressing part 30 can increase the internal pressure of the second space S2 through the channel 21a, thereby applying isotropic pressure to the soft capsule F, more specifically, applying isotropic pressure to the target area 110. Therefore, the target area 110 may be stretched into the first space S1 and then molded into the cup portion 110 .

More specifically, the pressing process (S30) may include a pre-molding process (S31), a primary molding process (S32), and a secondary molding process (S33).

Referring to FIG. 5A , during the pre-molding process (S31), the pressing part 30 may press the target area 110 in a state where the first space S1 is open. Here, the pressure applied by the pressing part 30 to the target area 110 can be appropriately adjusted so that the remaining thickness of the target area 110 is not excessively thin.

More specifically, in the pre-molding process S31, the remaining thickness of the stretched target area 110 may be approximately 90% of the thickness t of the soft coating F. That is, the thickness of the target area 110 may be reduced by approximately 10%, and the area of the target area 110 may be increased by approximately 10%.

As described above, since isostatic pressure is applied to the target area 110, the target area 110 can be evenly stretched into the first space S1 to form a predetermined curved surface. The curved surface of the target area 110 may be formed to have the lowest middle part and have a height that gradually increases toward the inner circumference of the first space S1.

More specifically, the curved surface formed by the target area 110 may form a part of an ellipsoid defined by Equation 1 below.

[Formula 1]

In Formula 1, x is the coordinate in the first direction parallel to the horizontal direction of the first space S1, y is the coordinate in the second direction parallel to the vertical direction of the first space S1, and z is the coordinate in the vertical direction. coordinates on. In addition, a is half of the first width W1, b is half of the second width W2, and c1 is the depth of the curved surface formed by the target area 110.

c1 can be proportional to the average of value a and value b. For example, when the thickness of the target area 110 is stretched to be reduced by approximately 10%, c1 may be approximately 0.4 times the average of the values a and b. Therefore, those skilled in the art will easily understand that if the value obtained by multiplying the value a and the value b is a constant, and the remaining thickness of the target area 110 is a constant, c1 is likely to decrease as the ratio of the value a and the value b approaches 1. Increase.

Referring to FIG. 5B , during the first initial molding process ( S32 ), the first punch 40 may be inserted into the first space S1 of the mold 10 . Here, the pressing part 30 can continuously maintain the pressure applied to the target area 110 .

In a state where the first punch 40 is inserted into the first space S1 , the middle part of the curved surface 41 of the first punch 40 may be disposed at a height lower than the top surface of the mold 10 . More specifically, the first punch 40 may be inserted into the first space S1 at a height that does not interfere with the stretched target area 110 in the pre-molding process S31.

The curved surface 41 of the first punch 40 may have an approximately symmetrical shape with respect to the curved surface formed by the stretched target area 110 in the pre-molding process ( S31 ). That is, the curved surface 41 of the first punch 40 may form part of an ellipsoid defined by the following equation 2.

[Formula 2]

In Formula 2, x is the coordinate in the first direction parallel to the horizontal direction of the first space S1, y is the coordinate in the second direction parallel to the vertical direction of the first space S1, and z is the coordinate in the vertical direction. coordinates on. In addition, a is half of the first width W1, b is half of the second width W2, and c2 is a value obtained by multiplying the average value of the value a and the value b by a predetermined correction constant k.

As described in Equation 1 above, when the thickness of the target area 110 is stretched to be reduced by approximately 10% in the pre-molding process (S31), c1 may be approximately 0.4 times the average value of a and b.

Therefore, the correction constant k can be determined within a predetermined range with an intermediate value of 0.4 so that c2 corresponds to c1. More specifically, the correction constant k may be 0.2 to 0.6, and may be appropriately determined according to the depth of the cup portion 110 to be molded.

Due to the shape of the curved surface 41 of the first punch 40, during the primary molding process (S32), a part of the target area 110 may be in close contact with the curved surface 41, and another part of the target area 110 may be in close contact with the inner circumference of the first space S1 touching or adjacent. Hereinafter, a part of the target area 110 will be called a first area 111 , and another part of the target area 110 will be called a second area 112 .

Thereafter, the first region 111 may be molded as the bottom surface of the cup 110 , and the second region 112 may be molded as the peripheral surface of the cup 110 . Therefore, the bottom surface of the cup 110 is denoted by the same reference numeral 111 as the first region 111 , and the peripheral surface of the cup 110 is denoted by the same reference numeral 112 as the second region 112 .

Since the first region and the second region 112 are formed separately from each other in advance in the primary molding process (S32), the second region 112 can be easily stretched in the subsequent secondary molding process (S33). Therefore, there is an advantage that the cup portion 110 is molded deeply without causing wrinkles due to curvature on the peripheral surface 112 of the cup portion 110 .

In addition, since the positions where the first region 111 and the second region 112 intersect each other form an acute angle, the second region 112 can easily come into close contact with the inner periphery of the first space S1 in the subsequent secondary molding process (S33). Therefore, the peripheral surface 112 of the cup 110 may be formed perpendicular to the bottom surface 111 , and the radius of curvature of each of the edges and corners of the cup 110 may be minimized to prevent stress from being concentrated on the corners of the cup 110 .

Referring to FIG. 5C , during the secondary molding process S33 , the second punch 40 may be inserted into the first space S1 of the mold 10 . More specifically, when the primary molding process (S32) is completed, the first punch 40 may be separated from the first space S1 of the mold 10, and the second punch 40 may be inserted into the first space S1 of the mold 10, so that the second punch 40 is performed. Secondary molding process (S33).

In a state where the second punch 50 is inserted into the first space S1 , the flat surface 51 of the second punch 50 may be provided at a height lower than the top surface of the mold 10 .

More specifically, during the primary molding process (S32), the second punch 50 may be inserted into the first space S1 at a lower height than the first punch 40. That is to say, the height difference h2 between the flat surface 51 and the top surface of the mold 10 when the second punch 50 is inserted into the first space S1 may be greater than the height difference h2 between the curved surface 41 and the mold 10 when the first punch 40 is inserted into the first space S1. The height difference h1 between the top surfaces.

In addition, the pressure applied to the soft envelope F (more specifically, the target area 110) in the secondary molding process (S32) may be higher than the pressure in the primary molding process (S32). That is, compared with the state in which the first punch 40 is inserted into the first space S1, the pressing part 30 can apply greater pressure when the second punch 50 is inserted into the first space S1.

Therefore, during the secondary molding process (S33), the first area 111 may be in close contact with the flat surface 51 of the second punch 50, and the second area 112 may be in close contact with the inner periphery of the first space S1. Therefore, molding of the cup portion 110 can be completed.

More specifically, the first region 111 may be horizontally molded as the bottom surface of the cup 110 , and the second region 112 may be vertically molded as the peripheral surface of the cup 110 . In addition, since the second region 112 is stretched downward during the secondary molding process (S33), the depth of the cup portion 110 can be sufficiently deep.

The primary molding process (S32) may be directly performed without including the pressing process (S30) of the preliminary molding process (S31). In this case, the pressing part 30 may initiate pressing on the target area 110 in a state where the first punch 40 is inserted into the first space S1 of the mold 10 .

6 is an exploded perspective view showing the secondary battery according to the embodiment of the present invention.

The secondary battery 1 according to the present invention may include a pouch-type battery case 100 (hereinafter, referred to as a "battery case") and an electrode assembly 200 accommodated in the battery case 100 .

The battery case 100 can be molded by the above-described molding equipment and molding method. The battery case 100 may include a cup 110 having a concave shape and a platform 120 disposed on at least a portion of the periphery of the cup 110 . The platform 120 may be a part of the soft capsule F that does not form the cup 110 .

More specifically, the battery case 100 may be provided by sealing a pair of cases 102 and 22 connected to each other by a folding portion 130 . However, the present invention is not limited thereto, and the pair of cases 101 and 102 may be sealed in a separated state from each other to provide the battery case 200 .

In addition, at least one of the pair of housings 101 and 102 may be provided with a cup 110 having a concave shape. The cup 110 may be recessed from the platform 120 to a predetermined depth to define a space for receiving the electrode assembly 200 . Hereinafter, it will be described as an example that a pair of housings 101 and 102 includes a first housing 101 provided with a cup portion 110 and a second housing 102 provided with no cup portion 110 .

The first housing 101 may include a platform 120 disposed at at least a portion of the circumference of the cup 110 . More specifically, the platform 120 may be connected to an upper end of the peripheral surface 112 of the cup 110 .

In a state where the electrode assembly 200 is accommodated in the cup part 110 , the folding part 220 may be folded so that the second housing 102 covers the cup part 110 . In addition, the secondary battery 1 can be provided by welding the edge portion of the platform 101 and the second case 102 to provide the sealing portion 140 (see FIG. 8 ), thereby manufacturing the secondary battery 1 .

The electrode assembly 200 may include a plurality of electrodes 210 (see FIG. 8 ) and a plurality of separators 220 that are alternately stacked. A plurality of electrodes 210 are alternately stacked with a separator 220 interposed therebetween, and may include positive and negative electrodes with opposite polarities.

In addition, the electrode assembly 200 may include a plurality of electrode tabs 230 welded to each other. The plurality of electrode tabs 230 may be connected to the plurality of electrodes 210 and protrude to the outside from the electrode assembly 200 to serve as passages through which electrons move between the inside and outside of the electrode assembly 200 . A plurality of electrode tabs 230 may be provided inside the battery case 100 .

The electrode tab 230 connected to the positive electrode and the electrode tab 230 connected to the negative electrode may protrude in different directions relative to the electrode assembly 200 . However, the present invention is not limited thereto, and the electrode tab 230 connected to the positive electrode and the electrode tab 230 connected to the negative electrode may protrude in the same direction in parallel with each other.

The lead wire 240 that supplies power to the outside of the secondary battery may be connected to the plurality of electrode tabs 230 by spot welding or the like. The lead wire 240 may have one end connected to the plurality of electrode tabs 230 and the other end protruding to the outside of the battery case 100 .

A portion of the lead wire 240 may be surrounded by the insulating portion 250 . For example, the insulating portion 250 may include insulating tape. The insulating tape 250 may be disposed between the platform 120 and the second housing 102 of the first housing 101, and in this state, the platform 120 and the second housing 102 may be thermally welded to each other. In this case, a portion of each of the platform 120 and the second housing 102 may be thermally welded to the insulating portion 250 . Therefore, the insulating portion 250 can prevent the electricity generated from the electrode assembly 200 from flowing to the battery case 100 through the lead wire 240, and can maintain the sealing of the battery case 100.

7 is an enlarged view of part A of FIG. 6 , FIG. 8 is a cross-sectional view showing the inside of a secondary battery according to an embodiment of the present invention, and FIG. 9 is an enlarged view of part B of FIG. 8 .

Hereinafter, the configuration of the cup portion 110 of the battery case 100 will be described in detail.

The cup portion 110 may include a bottom surface 111 and a peripheral surface 112 . Perimeter 112 may connect bottom surface 112 to platform 120 . The number of peripheral surfaces 112 may be multiple, more specifically, four.

The bottom surface 111 may cover one surface of the electrode assembly 200 , and the peripheral surface 112 may surround the electrode assembly 200 .

In addition, the cup 110 may include a first edge 113 where the circumferential surface 112 and the platform 120 intersect with each other, a second edge 114 where the bottom surface 111 and the circumferential surface 112 intersect with each other, and a pair of circumferential surfaces 112 adjacent to each other. The third edge 115 where the faces intersect each other. Each of the edges 113, 114, 115 may be rounded to have a predetermined radius of curvature.

In addition, the cup portion 110 may include a corner portion 116 where a pair of adjacent peripheral surfaces 112 among the plurality of peripheral surfaces 112 and the bottom surface 111 intersect with each other. That is, the corner portion 116 may be a portion where a pair of second edges 114 and third edges 115 adjacent to each other are stacked on each other. Corner 116 may have a predetermined radius of curvature.

Since the cup portion 110 has four peripheral surfaces 112, each of the edges 113, 114, and 115 and the corner portion 116 may be provided with four.

In the molding apparatus and the molding method according to the embodiment of the present invention, stress concentration on each of the edges 113, 114, and 115 and the corner portion 116 can be minimized. Therefore, the radius of curvature of each of the edges 113, 114, and 115 and the corner portion 116 can be sufficiently small, and at the same time, the remaining thickness of the corner portion 116 can be sufficiently thick.

More specifically, at least a portion of the plurality of edges 113, 114, and 115 may have a radius of curvature of 0.1 mm or more and less than 0.5 mm. The radius of curvature R1 of the first edge 113 may be a radius of curvature relative to the outer surface of the first edge 113 . The radius of curvature R2 of the second edge 114 may be relative to the radius of curvature of the inner surface of the second edge 114 .

Additionally, the corner portion 116 may have a radius of curvature in the range of 0.75 mm to 1.25 mm. The radius of curvature of the corner portion 116 may be a radius of curvature relative to the inner surface of the corner portion 116 .

On the other hand, since the cup part according to the related art is molded by direct press of the punch, the stretching may be concentrated on each of the edges and corners of the cup part, and therefore, each edge may have 0.5 mm to 1 mm The radius of curvature, and the corners can have a radius of curvature of 1.5mm to 3mm to prevent cracks, etc. from appearing in each of the edges and corners. This is a well-known fact to those skilled in the art. Therefore, it can be seen that the radius of curvature of each of the edges 113, 114, 115 and the corner portion 116 of the cup portion 110 according to the embodiment of the present invention is smaller than that of the cup portion according to the related art.

Since the curvature radius of each of the edges 113, 114, 115 and the corner portion 116 is small enough, the appearance of the cup portion 110 can be sharply formed. Furthermore, even if the electrode 210 of the electrode assembly 200 is disposed very close to the peripheral surface 112 of the cup 110 , interference between the electrode 210 and the cup 110 can be prevented.

That is, since the electrode 210 of the electrode assembly 200 is disposed very close to the peripheral surface 112 of the cup 110, the empty space in the cup 110 can be reduced, and the energy density of the secondary battery can be increased, thereby preventing the electrode assembly from 200 moves inside the cup 110 . In this case, the edge portion 220 a of the diaphragm 220 that protrudes outward from the electrode 210 may be folded so as to be in contact with the circumferential surface 111 of the cup portion 110 . The edge portion 220a of the diaphragm 220 may be folded randomly or in a predetermined direction. For example, the edge portion 220a of the diaphragm 220 may be folded toward the opposite direction of the bottom surface 111.

In addition, the thickness of the corner portion 16 may be 0.75 to 0.85 times the thickness of the bottom surface 111 . That is, the thickness of the corner portion 16 may be less than 15% to 25% of the thickness of the bottom surface 111 . In this case, the thickness of the bottom surface 111 may be a thickness measured at the center of the bottom surface 111 , and the thickness of the corner portion 16 may be a thickness measured at the center of the corner portion 16 .

On the other hand, since the cup portion according to the related art is molded by direct pressing of the punch, stretching may be concentrated at the center of the cup portion, and therefore, the thickness of the corner portion of the cup portion may be greater than the thickness of the bottom surface of the cup portion 30% to 40% smaller. This is a well-known fact to those skilled in the art. Therefore, when compared with the cup portion according to the related art, it was confirmed that the remaining thickness of the corner portion 116 of the cup portion 110 according to the embodiment of the present invention is thicker.

Since the remaining thickness of the corner portion 116 is thick enough, no cracks or holes will appear in the corner portion 116 . Additionally, the cup 110 may be provided deeper.

In the molding apparatus and the molding method according to embodiments of the present invention, the peripheral surface 112 of the cup portion 110 may be disposed nearly perpendicular to the bottom surface 111 . More specifically, the angle formed by the peripheral surface 112 of the cup 110 relative to the bottom surface 111 or the platform 120 of the cup 110 may be 90 degrees to 95 degrees.

Therefore, the gap CL between the first edge 113 and the second edge 114 can be minimized. In this case, the gap CL may represent a virtual first vertical line V1 that vertically passes through the boundary point P1 between the first edge 113 and the peripheral surface 112 and a virtual first vertical line V1 that vertically passes through the boundary between the second edge 114 and the peripheral surface 112 The distance between point P2 and virtual second vertical line V2.

More specifically, the gap CL between the first edge 113 and the second edge 114 may be 0.1 mm or less. When the peripheral surface 112 of the cup 110 is completely vertical, the gap CL may be zero.

In addition, the gap CL between the first edge 113 and the second edge 114 may be less than or equal to each of the curvature radius R1 of the first edge 113 and the curvature radius R2 of the second edge 114 .

Therefore, since the empty space in the cup portion 110 is further reduced, the energy density of the secondary battery can be increased, and the appearance of the secondary battery can be further improved.

Figure 10 is a schematic diagram of a molding apparatus according to another embodiment of the present invention.

Hereinafter, differences will be focused on and the same contents as those of the molding apparatus according to the above-described embodiment will be described.

The molding apparatus according to this embodiment may further include a flexible bag 23 and a bag body 24 .

The flexible bag 24 may be disposed in the second space S2 of the stripper 20 (see Figure 2). Flexible bag 24 may be in contact with soft envelope F (more specifically, target area 110). The flexible bag 24 may be expanded by the pressing part 30 to apply pressure to the target area 110, and the target area 110 may be stretched into the first space S1.

The bag body 24 can be connected to the flexible bag 23 . The bag body 24 can seal the inner space of the flexible bag 23 . That is, the inner space of the flexible bag 23 may be defined by the flexible bag 23 and the bag body 24 .

In addition, the bag body 24 may seal the second space S2 of the stripper 20 . More specifically, the second space S2 of the demolder 20 according to this embodiment may be open to the upper side. In addition, in a state where the flexible bag 23 is inserted into the second space S2, the bag body 24 may cover the second space S2 from the upper side. That is, the bag main body 24 can be used as the lid portion 21 described in the previous embodiment (see FIG. 2 ).

In addition, the bag body 24 may be provided with a passage 24 a that communicates the pressing part 30 and the inner space of the flexible bag 23 with each other.

The pressing part 30 according to this embodiment can control the internal pressure of the flexible bag 23 by introducing fluid through the channel 24a. The term "fluid" includes liquids and gases. That is, the pressing part 30 may apply air pressure or hydraulic pressure to the target area 110 . For example, the pressing part 30 may include a pneumatic pump or a hydraulic pump.

Therefore, when the internal pressure of the flexible bag 23 is higher than the internal pressure of the first space S1 (eg, atmospheric pressure), the target area 110 can be stretched to the first space through the pressure difference between the first space S1 and the flexible bag 23 . in space S1.

That is, since a balanced pressure is applied to the target area 110, in the process of stretching the target area 110, the thickness t of the target area 110 can be uniformly reduced as a whole. Therefore, stress concentration in the local area of the target area 110 can be minimized.

In particular, when the pressing part 30 uses liquid to apply hydraulic pressure to the soft coating F, the liquid will not come into contact with the demolder 20 and the soft coating F through the flexible bag 23. Therefore, the possibility of breakage or malfunction of the molding equipment due to liquid can be eliminated.

Those skilled in the art can easily understand that the molding method according to the above-described embodiment can be performed by a molding apparatus according to another embodiment of the present invention, and the cup portion 110 of the battery case 100 can be molded.

Figure 11 is a schematic diagram of a molding apparatus according to yet another embodiment of the present invention.

A molding apparatus according to yet another embodiment of the present invention does not include the first punch 40 and the second punch 50 , but uses air pressure or hydraulic pressure on both sides of the soft envelope F to mold the cup portion 110 .

Hereinafter, as in the other embodiments described above, the case where the pressing part 30 applies hydraulic pressure to the soft capsule F will be described as an example. In addition, for convenience of description, the flexible bag 23 is called a "first flexible bag" and the bag body 24 is called a "first bag body". However, the present invention is not limited thereto. Of course, as in the above-described exemplary embodiment, the pressing part 30 may also apply air pressure to the soft capsule F.

The molding apparatus according to another embodiment of the present invention may further include a lower body 60 , a second flexible bag 63 , a second bag body 34 and a sub-pressing part 70 .

The lower body 60 may be disposed below the mold 10 . A third space S3 communicating with the first space S1 of the mold 10 may be defined in the lower body 60 . The lower body 60 may be manufactured separately from the mold 10 . However, the present invention is not limited thereto, and the lower body 60 and the mold 10 may be integrally formed with each other.

The second flexible bag 63 may be disposed in the third space S3 and expanded into the first space S1 to contact the soft envelope F.

The second bag body 64 may be connected to the second flexible bag 63 . The second bag body 64 can seal the inner space of the second flexible bag 63 . That is, the inner space of the second flexible bag 63 may be defined by the second flexible bag 63 and the second bag body 64 .

In addition, the second bag body 64 may seal the third space S3 of the lower body 60 . More specifically, the third space S3 may be open to the lower side, and the second bag body 64 may cover the third space S2 from the lower side in a state inserted into the third space S3. In addition, the second bag main body 64 may be provided with a passage 64 a that communicates the sub-pressing part 70 and the inner space of the second flexible bag 63 with each other.

The sub-pressing part 70 can control the internal pressure of the second flexible bag 63 by introducing fluid through the channel 64a. The term "fluid" includes liquids and gases. That is, the sub-pressing part 70 may apply air pressure or hydraulic pressure to the target area 110 . For example, the sub-pressing part 70 may include a pneumatic pump or a hydraulic pump.

The distance d1 between the soft covering film F and the first bag body 24 may be smaller than the distance d2 between the soft covering film F and the second bag body 64 . Therefore, the first flexible bag 23 can press the target area 110 uniformly as a whole, while the second flexible bag 63 can press only a part of the target area 110 according to the expansion degree, or the target area 110 can be pressed as a whole. This will be described in more detail.

12 is a flowchart showing a molding method performed using a molding apparatus according to yet another embodiment of the present invention, and FIGS. 13A to 13C are diagrams illustrating operations of the molding apparatus according to yet another embodiment of the present invention. .

The molding method according to this embodiment may include: a preparation process (S10) of inserting the soft coating film F between the mold 10 and the demoulding device 20, a fixing step (S20) of fixing the soft coating film F by the demoulding device 20, and A pressing process (S30) of applying air pressure or hydraulic pressure to the soft film.

The preparation process (S10) and the fixing process (S20) refer to the above-mentioned contents.

In the pressing process (S30'), the pressing part 30 can adjust the internal pressure of the first flexible bag 23, and the sub-pressing part 70 can adjust the internal pressure of the second flexible bag 63 to apply air pressure or hydraulic pressure to the soft envelope F. Therefore, isostatic pressure may act on the soft envelope F (more specifically, the target area 110 ), and the target area 110 may be stretched into the first space S1 , thereby being molded into the cup portion 110 .

More specifically, the pressing process (S30') may include a pre-molding process (S31'), a primary molding process (S32'), and a secondary molding process (S33').

Referring to FIG. 13A, in the pre-molding process (S31'), the first flexible bag 23 may press the soft envelope F, more specifically, the target area 110. Here, the pressure applied to the target area 110 may be appropriately adjusted so that the remaining thickness of the target area 110 is not excessively thin.

More specifically, the first flexible bag 23 may be expanded by the pressing part 30 to apply isostatic pressure to the target area 110 . Therefore, the target area 110 can be evenly stretched into the first space S1 to form a predetermined curved surface. The curved surface of the target area 110 may be formed to have the lowest middle part and have a height that gradually increases toward the inner circumference of the first space S1.

Referring to FIG. 13B, in the primary molding process (S32'), the second flexible bag 63 may be expanded into the first space S1 to press the soft capsule F, more specifically, the target area 110. Here, the first flexible bag 23 can continuously maintain the pressure applied to the target area 110 .

Since the second bag body 64 is disposed further than the first bag body 63 with respect to the soft envelope film F, the second flexible bag 63 may be in contact with a part of the middle part of the target area 110 in the primary molding process S32'. Here, the internal pressure of the second flexible bag 63 may be higher than the internal pressure of the first flexible bag 23 .

Therefore, a part of the target area 110 may be formed to protrude upward when pressed between the first flexible bag 23 and the second flexible bag 63 , and another part of the target area 110 may be spaced apart from the second flexible bag 62 and connected with the second flexible bag 62 . The inner peripheries of the first space S1 are in contact or adjacent to each other. Hereinafter, a part of the target area 110 will be called a first area 111 , and another part of the target area 110 will be called a second area 112 .

Since the first region and the second region 112 are formed to be separated from each other in advance in the primary molding process (S32'), the second region 112 can be easily stretched in the subsequent secondary molding process (S33'). Therefore, there is an advantage that the cup portion 110 is molded deeply without causing wrinkles due to curvature on the peripheral surface 112 of the cup portion 110 .

In addition, since the positions where the first region 111 and the second region 112 intersect each other form an acute angle, the second region 112 can easily come into close contact with the inner periphery of the first space S1 in the subsequent secondary molding process (S33'). . Therefore, the peripheral surface 112 of the cup 110 may be formed perpendicular to the bottom surface 111 , and the radius of curvature of each of the edges and corners of the cup 110 may be minimized to prevent stress from being concentrated on the corners of the cup 110 .

Referring to Fig. 13C, in the secondary molding process (S33'), the internal pressures of the first flexible bag 23 and the second flexible bag 63 may be adjusted to be equal to each other. In addition, in the primary molding process (S32'), the internal pressure of each of the first flexible bag 23 and the second flexible bag 63 may be greater than the internal pressure of the second flexible bag 63.

Therefore, the first area 111 can be pressed flatly between the first flexible bag 23 and the second flexible bag 63, and the second area 112 can be in close contact with the inner periphery of the first space S1. Therefore, molding of the cup portion 110 can be completed.

In the case of this embodiment, there is an advantage that a separate punch is not required, and the cup portion 110 is molded without raising and moving the mold 10 and the ejector 20 .

The subject matter disclosed above is to be regarded as illustrative rather than restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the disclosure.

Therefore, the embodiments of the present invention are considered to be illustrative rather than restrictive, and the technical spirit of the present invention is not limited to the foregoing embodiments.

Therefore, the scope of the disclosure is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present disclosure.

Claims (24)

1. A molding apparatus for molding a cup in a soft capsule, the molding apparatus comprising:

a mold, the soft envelope being disposed on a top surface of the mold and defining a first space therein recessed from the top surface;

a stripper disposed above the mold and fixing the soft envelope, and having a second space defined therein at a position corresponding to the first space; and

and a pressing portion configured to apply air pressure or hydraulic pressure to the soft capsule through the second space such that a portion of the soft capsule is stretched into the first space.

2. The molding apparatus of claim 1, wherein the ejector is provided with a cover portion configured to seal the second space on an upper side,

a passage that communicates the pressing portion and the second space with each other is provided in the ejector or the cover portion, and

the pressing portion controls an internal pressure of the second space by introducing or discharging gas through the passage.

3. The molding apparatus of claim 1, further comprising:

a flexible bag disposed in the second space to be in contact with the soft envelope; and

a bag body configured to seal the second space, the flexible bag being connected to the bag body, and a passage being provided in the bag body to communicate the pressing portion and the flexible bag with each other,

wherein the pressing portion controls an internal pressure of the flexible bag by introducing or discharging a fluid through the passage.

4. The molding apparatus of claim 1, further comprising a first punch inserted into the first space and having a curved surface protruding toward the soft capsule.

5. The molding apparatus of claim 4, wherein a middle portion of the curved surface is highest and a height of the curved surface gradually decreases toward an inner periphery of the first space.

6. The molding apparatus of claim 5, wherein the middle portion of the curved surface is disposed at a lower height than a top surface of the mold in a state where the first punch is inserted into the first space.

7. The molding apparatus of claim 4, wherein the first space has a first width in a first direction and a second width in a second direction perpendicular to the first direction, and

the curved surface is a part of an ellipsoid defined by the following formula 1:

where x is a coordinate in the first direction, y is a coordinate in the second direction, z is a coordinate in a vertical direction, a is half of the first width, b is half of the second width, and c is a value obtained by multiplying an average value of a value a and b by a correction constant k of 0.2 to 0.6.

8. The molding apparatus of claim 4, further comprising a second punch inserted into the first space and having a planar surface facing the soft capsule.

9. The molding apparatus of claim 8, wherein the pressing portion applies a greater pressure in a state in which the second punch is inserted into the first space than in a state in which the first punch is inserted into the first space.

10. The molding apparatus of claim 8, wherein a difference in height between the planar surface and the top surface of the mold when the second punch is inserted into the first space is greater than a difference in height between the curved surface and the top surface of the mold when the first punch is inserted into the first space.

11. The molding apparatus of claim 1, further comprising:

a lower body disposed below the mold and having a third space defined therein that communicates with the first space;

a flexible bag disposed in the third space and inflated into the first space to be in contact with the soft envelope;

a bag body configured to seal the third space, and the flexible bag is connected to the bag body; and

a sub-pressing portion configured to control an internal pressure of the flexible bag by introducing or discharging a fluid through a passage provided in the bag body.

12. A molding method of molding a cup in a soft capsule, the molding method comprising:

a preparation step of inserting the soft capsule between the mold and the ejector;

A fixing step of fixing the soft capsule by the stripper; and

and a pressing step in which a pressing portion applies air pressure or hydraulic pressure to the soft capsule through a second space formed in the ejector, so that a part of the soft capsule is stretched to the first space formed in the die.

13. The molding method according to claim 12, wherein the pressing process includes:

a primary molding process in which a first punch having a curved top surface is inserted into the first space of the mold and a portion of the soft capsule is in close contact with the curved surface, wherein the curved surface is formed convexly upward; and

and a secondary molding process in which a second punch having a planar top surface is inserted into the first space, and a portion of the soft capsule is in close contact with the planar surface.

14. The molding method according to claim 13, wherein the pressure applied to the soft capsule in the secondary molding process is greater than the pressure applied to the soft capsule in the primary molding process.

15. A molding method of molding a cup in a soft capsule, the molding method comprising:

A preparation step of inserting the soft capsule between the mold and the ejector;

a fixing step of fixing the soft capsule by the stripper; and

a pressing step of applying pneumatic or hydraulic pressure to the soft capsule so that a portion of the soft capsule is stretched to a first space formed in the mold to mold the cup portion,

wherein the pressing step includes:

a pre-molding process of stretching the soft envelope into the first space by a first flexible bag provided in a second space formed in the ejector;

a first molding process of expanding a first flexible bag into the first space to press a portion of the soft capsule so that the portion of the soft capsule is formed to be convexly formed upward; and

and a secondary molding step of adjusting the internal pressures of the first and second flexible bags to be the same so that a part of the soft capsule is formed flat.

16. The molding method according to claim 15, wherein in the primary molding process, an internal pressure of the second flexible bag is greater than an internal pressure of the first flexible bag.

17. The molding method of claim 16, wherein an internal pressure of each of the first flexible bag and the second flexible bag in the secondary molding process is greater than an internal pressure of the second flexible bag in the primary molding process.

18. A soft pack battery case comprising:

a cup portion having a concave shape; and

a platform disposed on at least a portion of a circumference of the cup,

wherein, the cup includes:

a bottom surface;

a plurality of peripheral surfaces configured to connect the bottom surface and the platform; and

a corner portion formed by a pair of peripheral surfaces adjacent to each other of the plurality of peripheral surfaces and the bottom surface intersecting each other,

wherein the thickness of the corner is 0.75 to 0.85 times the thickness of the bottom surface.

19. The soft pack battery case of claim 18, wherein the peripheral surface makes an angle of 90 degrees to 95 degrees with respect to the bottom surface or the platform.

20. The soft pack battery housing of claim 18, wherein the corners have a radius of curvature of 0.75mm to 1.25 mm.

21. The soft pack battery housing of claim 18, wherein the cup further comprises:

a first edge on which the peripheral surface and the platform intersect each other, and which is rounded; and

a second edge on which the bottom surface and the peripheral surface intersect each other, the second edge being rounded,

Wherein a gap between the first edge and the second edge is 0.1mm or less.

22. The soft pack battery housing of claim 21, wherein each of the first edge and the second edge has a radius of curvature of 0.1mm or more and less than 0.5 mm.

23. The soft pack battery housing of claim 18, wherein the cup further comprises:

a first edge on which the bottom surface and the peripheral surface intersect each other, and which is rounded; and

a second edge on which the peripheral surface and the land intersect each other, and which is rounded,

wherein a gap between the first edge and the second edge is less than a radius of curvature of each of the first edge and the second edge.

24. A secondary battery, comprising:

an electrode assembly; and

a pouch-type battery case including a cup portion having a concave shape and a platform provided on at least a portion of the circumference of the cup portion,

wherein, the cup includes:

a bottom surface;

a plurality of peripheral surfaces configured to connect the bottom surface and the platform; and

A corner portion formed by a pair of peripheral surfaces adjacent to each other of the plurality of peripheral surfaces and the bottom surface intersecting each other,

wherein the thickness of the corner is 0.75 to 0.85 times the thickness of the middle portion of the bottom surface.